Research Interests:
The non-availability of ellipsoidal heights of local geodetic Datums has made it necessary for the application of ellipsoidal heights transformation models to the available global ellipsoidal heights to obtain their respective theoretical... more
The non-availability of ellipsoidal heights of local geodetic Datums has made it necessary for the application of ellipsoidal heights transformation models to the available global ellipsoidal heights to obtain their respective theoretical heights in local Datums. It is required to know the accuracy, as well as reliability of any model of interest before its application. For that reason, this study comparatively analyses the Molodensky and Kotsakis models for the transformation of ellipsoidal heights between geocentric and non-geocentric Datums to determine the reliability of the Kotsakis model. The Global Navigation Satellite System (GNSS) data of the used stations were processed in World Geodetic System 1984 (WGS84) datum to obtain their global geographic coordinates and ellipsoidal heights. The coordinates, ellipsoidal heights and the transformation parameters between WGS84 and Minna Datums were applied to the Molodensky and Kotsakis models to compute the Clarke 1880 theoretical h...
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The application of the transformation geoid model in Benin City has necessitated its fitting to the existing gravimetric-geometric geoid model of the study area. The transformation geoid model was determined using the Kotsakis (2008)... more
The application of the transformation geoid model in Benin City has necessitated its fitting to the existing gravimetric-geometric geoid model of the study area. The transformation geoid model was determined using the Kotsakis (2008) model for the transformation of global geoid heights to local geoidal undulations. To obtain its accuracy, the root mean square error (RMSE) index was applied. The computed accuracy is 2.0172 m. To apply the determined geoid model in the study area, as well as improving on the computed accuracy, the model was fitted to the gravimetric-geometric geoid model of the study area. The fitting result shows that geoid heights can be computed using the determined geoid model with an accuracy of 1.1041 m in the study area.
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Differential GPS/GNSS positioning gives accurate coordinates as well as positions of observed points on the earth surface. To obtain the accuracy as well as the reliability and the most probable positions of observed points using the post... more
Differential GPS/GNSS positioning gives accurate coordinates as well as positions of observed points on the earth surface. To obtain the accuracy as well as the reliability and the most probable positions of observed points using the post processing software that accompanies the receivers, least squares adjustment technique is applied. Applying least squares adjustment technique requires three or more receivers, that is two or more rovers and one base receiver to be used. Using three or more receivers makes the observation a closed loop observation. But in most cases where the number of points whose positions are to be determined is small, the observations are carried out with only two (rover and base) receivers. Using only two receivers (rover and base) implies that each of the points will be occupied one after the other with respect to the base receiver. In this, least squares adjustment cannot be applied as the observation is not a closed loop one, hence, the accuracy of the obse...
Research Interests:
Safety is the primary and most important reason for monitoring the deformations of engineering structures. It could also help in improving our knowledge of the mechanical behaviour of engineering structures. Engineering structures are... more
Safety is the primary and most important reason for monitoring the deformations of engineering structures. It could also help in improving our knowledge of the mechanical behaviour of engineering structures. Engineering structures are subject to deformation due to factors such as changes of ground water level, traffic load changes, tidal and tectonic<br> phenomena. The Ikpoba River Bridge in Benin City whose traffic load has increased was monitored using GPS technology. The bridge was investigated as a result of carrying more load than usual due to the expansion of the road and dredging activities that had taken place in the river in 2008. One reference station and six monitoring points were involved in the monitoring of the bridge. The regularity of the survey was thirty days, and six observation epochs were used. Each monitoring point was occupied for about thirty minutes during the observation. The observation data were processed with compass software. The processed coordin...
Research Interests:
Since positions are computed on the local ellipsoids adopted for geodetic computation in various countries and as some of the geographic positions of the reference/control stations in Nigeria were determined on the WGS 84 ellipsoid, this... more
Since positions are computed on the local ellipsoids adopted for geodetic computation in various countries and as some of the geographic positions of the reference/control stations in Nigeria were determined on the WGS 84 ellipsoid, this paper has comparatively analyzed three geodetic datum transformation software with a view to determining which of them is most suitable for transformation between WGS 84 and Minna datums. The positions of five points obtained from the processing of GNSS observations using Compass post processing software were used. The WGS 84 geographic coordinates were transformed and converted to rectangular coordinates on the Minna datum using Columbus, AllTrans and GeoCalc software. The transformed and converted coordinates of the points were compared with the rectangular coordinates of the points obtained with Compass software to determine which of the software is most suitable for application between WGS 84 and Minna datums. The comparison results show that Co...
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A local geoid model for Evboriaria, Benin City using the geometric (GPS/Levelling) method was determined for calculation of mean sea level heights. Fifty points were established for the model and ten points were used for interpolation.... more
A local geoid model for Evboriaria, Benin City using the geometric (GPS/Levelling) method was determined for calculation of mean sea level heights. Fifty points were established for the model and ten points were used for interpolation. The geoid heights were determined by finding the difference between the observed orthometric heights and the ellipsoidal heights. The polynomial regression model D was used for the interpolation of the orthometric heights. The computed mean standard deviation between the observed orthometric heights and the interpolated orthometric heights was ± 21cm. A mean geoidal undulation of 28.410m was computed using the gravimetric method. The computed orthometric heights using the gravimetry mean geoidal undulation were compared with the observed orthometric heights and seen to be identical. It is recommended that orthometric heights of project areas should be determined from GPS observations with the local geoid model of the area also determined.
Research Interests:
Global Positioning System (GPS) static measurements require post-processing to determine 3-D positions coordinates i.e. Eastings, Northings, and ellipsoidal height (E, N, h) of various points of interests. The adoption of differential GPS... more
Global Positioning System (GPS) static measurements require post-processing to determine 3-D positions coordinates i.e. Eastings, Northings, and ellipsoidal height (E, N, h) of various points of interests. The adoption of differential GPS (DGPS) approach for data capture improves on the positionaldata. Use of dual frequency Hi-Target V30 Pro geodetic receivers also enhancesthe reliability and quality of GPS measurementsthrough online processors. Online post-processing software (OPUS, CSRS-PPP, magicGNSS) were used to process the uploaded Receiver INdependent EXchange format (RINEX) data for the GPS position determination. ANOVA statistics was used to analyze the results. Computed F-testvalues compared against critical F-test table values and hypothesis testing was carried out. The results indicate that there is no significant difference between the three online post processing software.It is recommended that any of the online post-processing software canbe used interchangeably to pr...
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For the reason that there are several factors that affect large engineering structures, monitoring them to determine their deformations for safety purpose cannot be underestimated. Therefore, this study presents monitoring and analysis of... more
For the reason that there are several factors that affect large engineering structures, monitoring them to determine their deformations for safety purpose cannot be underestimated. Therefore, this study presents monitoring and analysis of vertical and horizontal deformations of a large structure, Palm House Building, Benin City, to determine its structural integrity. Four reference stations, two sets of monitoring points and two conventional geodetic techniques, total station and digital level were used. The positions and heights of the reference stations were respectively determined using CHC900 dual frequency GNSS receivers and digital level with respect to nearby control station and benchmark. The two sets of monitoring points were observed at three epochs at interval of six months using total station and digital level with respect to the reference stations. The observations were adjusted with least squares technique to determine the reliability as well as the accuracy of the adj...
Research Interests:
The reconciliation of engineering designs that do not have survey information, that involve accurate configuration of the proposed constructions at their respective locations on-site requires first a topographic survey to obtain the... more
The reconciliation of engineering designs that do not have survey information, that involve accurate configuration of the proposed constructions at their respective locations on-site requires first a topographic survey to obtain the perimeter survey plan, which in turn, shows the area, shape, perimeter and orientation of the site; spot heights plan showing the existing ground levels thereby used to decide on suitable gradients and determine appropriate finished ground surface, coordinates of the turning points of outlines of the proposed constructions and their respective elevations. For that reason, this study determines the topography and drains the site for the Benin City Bus Rapid Transit (BRT) station in Oredo Local Government Area of Edo State. A topographic survey was carried out to produce topographic plans. The accuracy of the survey was computed to determine its reliability. The perimeter survey plan was plotted using AutoCAD Civil 3D Land Desktop Companion 2009 to present...
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The proposed transformation of the global geoid model method for the determination of the local geoid model of Nigeria has only been applied in part of the Federal Capital Territory, Abuja. To determine the consistency of the accuracy of... more
The proposed transformation of the global geoid model method for the determination of the local geoid model of Nigeria has only been applied in part of the Federal Capital Territory, Abuja. To determine the consistency of the accuracy of the method for the intended purpose, there is a need to apply it in some other parts of the country. As a result, this study presents the verification of the consistency of the proposed transformation of global geoid method accuracy for local geoid model of Nigeria determination. DGNSS observations were carried out to obtain the coordinates of the used points. The processed global geographic coordinates were used with online software (GeoidEval) to obtain the EGM 08 geoid heights of the points. The global geographic coordinates, the global geoid heights of the points and the transformation parameters from WGS 84 to Minna datum were applied to obtain the transformed (local) geoid heights of the points using a Microsoft Excel program. The transformed ...
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The importance of practical, as well as orthometric heights in engineering cannot be underestimated as it is required for the determination of proposed construction levels and to direct the flow of water. This study presents the... more
The importance of practical, as well as orthometric heights in engineering cannot be underestimated as it is required for the determination of proposed construction levels and to direct the flow of water. This study presents the determination of orthometric heights of points using gravimetric/GPS and geodetic levelling approaches and compares the resolution of the two approaches to determine which of the methods is better for orthometric height determination in the study area. A total of 59 stations were occupy for gravity observation using Lacoste and Romberg (G-512 series) gravimeter to obtain the absolute gravity values of the points. GNSS observation was carried out in static mode using South GNSS receivers to obtain the positions and ellipsoidal heights of the points. The modified Stokes’ integral was applied to obtain the geoid heights of the points. Similarly, levelling was carried out using the geodetic level to obtain the level heights of the points. The orthometric correct...
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The direct determination of NTM and UTM plane rectangular coordinates from post processing of static DGPS/GNSS observations on the Nigeria Minna datum using post processing software is feasible if the rectangular NTM or UTM coordinates of... more
The direct determination of NTM and UTM plane rectangular coordinates from post processing of static DGPS/GNSS observations on the Nigeria Minna datum using post processing software is feasible if the rectangular NTM or UTM coordinates of the control/base station are known, and the belt or zone in which the observations were acquired is accurately identified and the identified belt or zone parameters correctly applied during data processing. But most users of these post processing software process these observations in NTM rectangular coordinates and subsequently convert the NTM grid coordinates to UTM grid positions which are not always correct. Consequently, this paper presents detailed procedures and feasibility of obtaining directly NTM or UTM coordinates from post processing of DGPS observations on the Nigeria Minna datum using the appropriate belt or zone parameters and post processing software that accompanied the DGPS/GNSS receivers. The procedures and feasibility of obtaini...
Research Interests:
The deflection of the vertical is an important parameter of the local gravity field which must not be neglected during survey measurements. In most survey (Geodetic) measurements, the components of deflection of the vertical are not... more
The deflection of the vertical is an important parameter of the local gravity field which must not be neglected during survey measurements. In most survey (Geodetic) measurements, the components of deflection of the vertical are not considered as a result of non availability of detailed maps in such area or region. The components of deflection of the vertical using the GPS/levelling (Geometric) method were determined. Fifteen ancillary stations and one control station were used. The orthometric and the ellipsoidal heights of the stations were determined using digital Level and GPS respectively. The least squares adjustment principle was carried out on the observations with the components as parameters. The values obtained are: -0.550” ± 0.000001” and - 0.395” ± 0.0000006” for ξ (north-south) and ƞ(east-west) directions respectively. The components of deflection of the vertical of the study area were also computed using three geopotential models (EGM08, EGM96 and EGM84). They are: ξ ...
The displacements of engineering structures have been investigated by different researchers using one of the various geodetic methods such as GPS, Total Station, Levelling, InSAR, Photogrammetry, Theodolite, EDM and 3D Laser but in that,... more
The displacements of engineering structures have been investigated by different researchers using one of the various geodetic methods such as GPS, Total Station, Levelling, InSAR, Photogrammetry, Theodolite, EDM and 3D Laser but in that, the accuracy of these methods have not really been compared to determine which of the methods is better in terms of accuracy, magnitude and direction of the expected deformation. This study monitored and modelled the deformation of Palm House in Benin City using GPS and Total Station and compared the accuracy of the two horizontal methods. Four reference stations and two sets of monitoring points were used. The DGPS observations were used to determine the roof monitoring points rectangular coordinates while the total station was used to determine the 10th floor base monitoring points rectangular coordinates and their bearings and distances from the reference stations. The observations were carried out at six epochs of three months interval and adjus...
The reconciliation of engineering designs that do not have survey information, that involve accurate configuration of the proposed constructions at their respective locations on-site requires first a topographic survey to obtain the... more
The reconciliation of engineering designs that do not have survey information, that involve accurate configuration of the proposed constructions at their respective locations on-site requires first a topographic survey to obtain the perimeter survey plan, which in turn, shows the area, shape, perimeter and orientation of the site; spot heights plan showing the existing ground levels thereby used to decide on suitable gradients and determine appropriate finished ground surface, coordinates of the turning points of outlines of the proposed constructions and their respective elevations. For that reason, this study determines the topography and drains the site for the Benin City Bus Rapid Transit (BRT) station in Oredo Local Government Area of Edo State. A topographic survey was carried out to produce topographic plans. The accuracy of the survey was computed to determine its reliability. The perimeter survey plan was plotted using AutoCAD Civil 3D Land Desktop Companion 2009 to present...
Research Interests:
Global Positioning System (GPS) static measurements require post-processing to determine 3-D positions coordinates i.e. Eastings, Northings, and ellipsoidal height (E, N, h) of various points of interests. The adoption of differential GPS... more
Global Positioning System (GPS) static measurements require post-processing to determine 3-D positions coordinates i.e. Eastings, Northings, and ellipsoidal height (E, N, h) of various points of interests. The adoption of differential GPS (DGPS) approach for data capture improves on the positional data. Use of dual frequency Hi-Target V30 Pro geodetic receivers also enhances the reliability and quality of GPS measurements through online processors. Online post-processing software (OPUS, CSRS-PPP, magicGNSS) were used to process the uploaded Receiver INdependent EXchange format (RINEX) data for the GPS position determination. ANOVA statistics was used to analyze the results. Computed F-test values compared against critical F-test table values and hypothesis testing was carried out. The results indicate that there is no significant difference between the three online post processing software. It is recommended that any of the online post-processing software can be used interchangeably...
Research Interests:
For the reason that there are several factors that affect large engineering structures, monitoring them to determine their deformations for safety purpose cannot be underestimated. Therefore, this study presents monitoring and analysis of... more
For the reason that there are several factors that affect large engineering structures, monitoring them to determine their deformations for safety purpose cannot be underestimated. Therefore, this study presents monitoring and analysis of vertical and horizontal deformations of a large structure, Palm House Building, Benin City, to determine its structural integrity. Four reference stations, two sets of monitoring points and two conventional geodetic techniques, total station and digital level were used. The positions and heights of the reference stations were respectively determined using CHC900 dual frequency GNSS receivers and digital level with respect to nearby control station and benchmark. The two sets of monitoring points were observed at three epochs at interval of six months using total station and digital level with respect to the reference stations. The observations were adjusted with least squares technique to determine the reliability as well as the accuracy of the adj...
Research Interests:
Differential GPS/GNSS positioning gives accurate coordinates as well as positions of observed points on the earth surface. To obtain the accuracy as well as the reliability and the most probable positions of observed points using the post... more
Differential GPS/GNSS positioning gives accurate coordinates as well as positions of observed points on the earth surface. To obtain the accuracy as well as the reliability and the most probable positions of observed points using the post processing software that accompanies the receivers, least squares adjustment technique is applied. Applying least squares adjustment technique requires three or more receivers, that is two or more rovers and one base receiver to be used. Using three or more receivers makes the observation a closed loop observation. But in most cases where the number of points whose positions are to be determined is small, the observations are carried out with only two (rover and base) receivers. Using only two receivers (rover and base) implies that each of the points will be occupied one after the other with respect to the base receiver. In this, least squares adjustment cannot be applied as the observation is not a closed loop one, hence, the accuracy of the obse...
Research Interests:
Safety is the primary and most important reason for monitoring the deformations of engineering structures. It could also help in improving our knowledge of the mechanical behaviour of engineering structures. Engineering structures are... more
Safety is the primary and most important reason for monitoring the deformations of engineering structures. It could also help in improving our knowledge of the mechanical behaviour of engineering structures. Engineering structures are subject to deformation due to factors such as changes of ground water level, traffic load changes, tidal and tectonic phenomena. The Ikpoba River Bridge in Benin City whose traffic load has increased was monitored using GPS technology. The bridge was investigated as a result of carrying more load than usual due to the expansion of the road and dredging activities that had taken place in the river in 2008. One reference station and six monitoring points were involved in the monitoring of the bridge. The regularity of the survey was thirty days, and six observation epochs were used. Each monitoring point was occupied for about thirty minutes during the observation. The observation data were processed with compass software. The processed coordinates were ...
Abstract: Although, there are various software that perform least squares adjustment of horizontal geodetic network so as to determine the precision and accuracy of the network. But the theories and equations that were used to develop the... more
Abstract: Although, there are various software that perform least squares adjustment of horizontal geodetic network so as to determine the precision and accuracy of the network. But the theories and equations that were used to develop the programs which the software are using are not quite understood by various user. This paper presents step by step procedures of horizontal geodetic network precision and accuracy determination using observation equation method of least squares technique. The detailed procedures are enumerated in sequential order for users understanding. The enumerated procedures are also demonstrated using a numeric example.
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A local geoid model for Evboriaria, Benin City using the geometric (GPS/Levelling) method was determined for calculation of mean sea level heights. Fifty points were established for the model and ten points were used for interpolation.... more
A local geoid model for Evboriaria, Benin City using the geometric (GPS/Levelling) method was determined for calculation of mean sea level heights. Fifty points were established for the model and ten points were used for interpolation. The geoid heights were determined by finding the difference between the observed orthometric heights and the ellipsoidal heights. The polynomial regression model D was used for the interpolation of the orthometric heights. The computed mean standard deviation between the observed orthometric heights and the interpolated orthometric heights was ± 21cm. A mean geoidal undulation of 28.410m was computed using the gravimetric method. The computed orthometric heights using the gravimetry mean geoidal undulation were compared with the observed orthometric heights and seen to be identical. It is recommended that orthometric heights of project areas should be determined from GPS observations with the local geoid model of the area also determined.
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The position occupied by the geoid in the computation of orthometric height (H) from GNSS observations is crucial and hence requires the geoid model parameters obtained with the application of least squares technique, be approximated to a... more
The position occupied by the geoid in the computation of orthometric height (H) from GNSS observations is crucial and hence requires the geoid model parameters obtained with the application of least squares technique, be approximated to a reasonable number of significant figures in its (geoid) modelling to enable a high-resolution geometric geoid, be determined. As a result, this study presents the implication of significant number in geodetic computations using geometric geoid model of FCT, Abuja as a case study. The number of significant figures of the model parameters was varied, starting from 6 to 22 significant figures to enable the Root Mean Square Errors (RMSEs), as well as the accuracy of the model, be obtained at the varied numbers of significant figures. The obtained results show that the highest accuracy of the model is obtained if the model parameters are approximated to a reasonable number of significant figures.
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Background: Orthometric height, as well as geoid modelling using the geometric method, requires centroid computation. And this can be obtained using various models, as well as methods. These methods of centroid mean computation have... more
Background: Orthometric height, as well as geoid modelling using the geometric method, requires centroid computation. And this can be obtained using various models, as well as methods. These methods of centroid mean computation have impacts on the accuracy of the geoid model since the basis of the development of the theory of each centroid mean type is different. This paper presents the impact of different centroid means on the accuracy of orthometric height modelling by geometric geoid method.Methods: DGPS observation was carried out to obtain the coordinates and ellipsoidal heights of selected points. The centroid means were computed with the coordinates using three different centroid means models (arithmetic mean, root mean square and harmonic mean). The computed centroid means were entered accordingly into a Microsoft Excel program developed using the Multiquadratic surface to obtain the model orthometric heights at various centroid means. The root means square error (RMSE) inde...
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The importance of the local geoid model for the computation of accurate geoid heights, as well as orthometric heights used for engineering constructions, necessitated its establishment in areas, regions or countries. Consequently, this... more
The importance of the local geoid model for the computation of accurate geoid heights, as well as orthometric heights used for engineering constructions, necessitated its establishment in areas, regions or countries. Consequently, this study establishes the local geometric geoid model of Busoga, Uganda, using the geometric method. A total of 26 points were used in the study, 20 points for the development of the model and 6 test points. GNSS observations were acquired with Trimble GNSS dual-frequency receivers and processed with Bernese (V5.2) and Spectra Precision Survey Office (v4.1) software to obtain the coordinates and ellipsoidal heights of the points. Differences between the existing orthometric and ellipsoidal heights were computed to obtain the geoid heights. The Least squares adjustment technique was applied to determine the fit, as well as the Bicubic and Multiquadratic models’ parameters. The Root Mean Squares Error (RMSE) index was used to compute the accuracy of the mod...
Research Interests: Model, Local, Geoid, Height, Geometrical Geodesy, and 4 moreEllipsoidal, Undulation, geometric, and Orthometric
The improvement of the accuracy of a local geometric geoid model using the same data set (geoid heights) requires the fitting of a higher degree polynomial surface to the data set. Consequently, this paper presents improving the local... more
The improvement of the accuracy of a local geometric geoid model using the same data set (geoid heights) requires the fitting of a higher degree polynomial surface to the data set. Consequently, this paper presents improving the local geometric geoid model of FCT, Abuja accuracy by fitting a higher order polynomial surface. A fifth degree polynomial surface was fit to the existing geoid heights of 24 points used previously for the determination of the geometric geoid model of the study area to improve its accuracy. The least squares adjustment technique was applied to compute the model parameters, as well as the fit. The RMSE index was applied to compute the accuracy of the model. The computed accuracy (0.081m) of the model was compared with those of the previously determined geoid models (Multiquadratic, 0.110m and Bicubic, 0.136m models) of the study area to determine which of the models best fit the study area, as well as has the highest resolution. The comparison result shows th...
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The conversion of theoretical, as well as geometric heights to practical heights requires the application of geoidal undulations from a geoid model. The various global geopotential models that are readily available for application in any... more
The conversion of theoretical, as well as geometric heights to practical heights requires the application of geoidal undulations from a geoid model. The various global geopotential models that are readily available for application in any part of the world do not best-fit regions, as well as countries. As a result, there is a need to determine the local geoid models of local areas, regions and countries. This study determines the local geoid model of Kampala in Uganda for orthometric heights computation by comparing three plane geometric geoid surfaces. A total of 19 points were used in the study. The least squares adjustment technique was applied to compute the models’ parameters. Microsoft Excel programs were developed for the application of the models in the study area. The Root Mean Square Index was applied to compute the accuracy of the models. The three geometric geoid models were compared using their accuracy to determine which of them is most suitable for application in the s...
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The understanding of the detailed procedures of the geodetic technique for structural deformation monitoring and analysis is required to enable a reliable and cost-effective monitoring system for the monitoring of engineering structures,... more
The understanding of the detailed procedures of the geodetic technique for structural deformation monitoring and analysis is required to enable a reliable and cost-effective monitoring system for the monitoring of engineering structures, be developed. To do this, the different stages that are involved in deformation studies using the geodetic method are explained in detail. As a result, this paper presents detailed geodetic technique procedures for structural deformation monitoring and analysis. Data collection, data processing, result presentation and analysis stages are discussed in detail.
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Research Interests: DISTRIBUTION, Model, Scientific, Spatial, Accuracy, and 5 moreGeoid, Distribution, multiquadratic, bicubic, and geometric
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As the application of gravity data in applied sciences such as geodesy, geodynamics, astronomy, physics and geophysics for earth shape determination, geoid model determination, computation of terrestrial mass displacement, orbit... more
As the application of gravity data in applied sciences such as geodesy, geodynamics, astronomy, physics and geophysics for earth shape determination, geoid model determination, computation of terrestrial mass displacement, orbit computation of natural and artificial celestial bodies, realization of force standards and derived quantities and density distribution in the different layers in the upper crust and having considered the cost of direct gravity survey, the study presents modelling local gravity anomalies from processed observed gravity measurements for geodetic application in Benin City. A total of 22 points were used. The points were respectively observed with CHC900 dual frequency GNSS receivers and SCINTREX CG-5 Autograv to obtain their coordinates and absolute gravity values. The theoretical gravity values of the points were computed on the Clarke 1880 ellipsoid to obtain their local gravity anomalies. The free air and the Bouguer corrections were applied to the computed ...
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As the Edo State Branch of the Nigerian Institution of Surveyors (NIS) has decided to align with the agency (Edo Geographic Information Service) that is responsible for the processing of Certificate of Occupancy to be determining... more
As the Edo State Branch of the Nigerian Institution of Surveyors (NIS) has decided to align with the agency (Edo Geographic Information Service) that is responsible for the processing of Certificate of Occupancy to be determining positions in the UTM system, the coordinates of the existing controls in the State have to be converted to UTM coordinates using conversion software. Consequently, this paper presents detailed procedures for the application of AllTrans and Columbus software for positions conversion between NTM and UTM systems in Minna datum. The Minna datum properties, as well as the NTM and UTM parameters, have been detailed for effective use. The step by step procedures to consider when applying the software have enumerated. It was recommended that the Edo State branch of the institution (NIS) should get the full and the latest version of the software. It was also recommended that there should be a lecture for the practical demonstration of the detailed procedures.
Research Interests: Software, Conversion, Columbus, NTM, UTM, and 5 moreCoordinates, CLARKE, Envirommental Sciences, MINNA DATUM, and AllTrans
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The accurate computation of positions of points from DGPS/GNSS observations acquired on the WGS84 ellipsoid in each country requires the application of transformation parameters. This is because, positions are determined with respect to... more
The accurate computation of positions of points from DGPS/GNSS observations acquired on the WGS84 ellipsoid in each country requires the application of transformation parameters. This is because, positions are determined with respect to the local datum/ellipsoid adopted for geodetic computation in each country. Prior to the derivation of the new/unified transformation parameters which were recently published by the Office of the Surveyor-General of the Federation, OSGOF, various sets of transformation parameters were determined by different multinational oil companies for use in Nigeria. Since the positions of reasonable number of points had been computed using these old sets of transformation parameters before the new/unified ones were derived and promulgated, there is need to verify which of the positions computed with the old sets of transformation parameters agree with the positions computed with the new/unified ones. Consequently, this paper compares the positions computed from DGPS/GNSS observations using the various, old sets and the unified transformation parameters. GNSS observations of four different points were processed with Compass post processing software using the various, old sets and the unified transformation parameters to obtain the positions of the points. The coordinates of each point obtained from the processing of the observations using the old sets of transformation parameters were compared with those obtained using the unified ones. The comparison results show that the positions computed using three different (SPDC, AGIP and DMA) sets of transformation parameters agree with those computed using the unified ones.
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Consistency is an important characteristic in height systems which the mean sea level (msl) surface cannot guarantee. Only a geoid surface can provide height consistency. The quality of geoid undulation (N) will obviously affect the... more
Consistency is an important characteristic in height systems which the mean sea level (msl) surface cannot guarantee. Only a geoid surface can provide height consistency. The quality of geoid undulation (N) will obviously affect the resulting orthometric height (H) determined from GNSS. The geoid undulation may be global, regional/national and local. Online software CSRS-PPP was used for post processing rinex data. N^EGM2008was computed from AllTrans EGM2008 geoid calculator while h was used to compute N^GPS from the relationship N= h-H. H is the existing orthometric height. Twenty-four controls with FCT 260 P as base reference station were used for this study. The computed standard deviation of differences inN^GPS- N^EGM2008 (σ) is used as accuracy indicator and σ =0.419m .The root mean square error (RMSE) is 0.934m. This indicates the quality and reliability of the geoid undulation from the EGM2008 model. Comparing the observed N^GNSSand N^EGM2008 , the use of global models may no...
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As the surface adopted for geodetic computation is a adopted as a reference for the vertical coordinate system, the ellipsoidal heights obtained from GPS observation are transfor to practical heights known as orthometric heights the... more
As the surface adopted for geodetic computation is a adopted as a reference for the vertical coordinate system, the ellipsoidal heights obtained from GPS observation are transfor to practical heights known as orthometric heights the knowledge of the geoid-ellipsoid separation at the point of observation. Since the geometric method requires the computation of geoid heights of points from GPS observation and prone to human errors, the accurate geoid heights of the points should be obtained from gravity measurement and a geometric geoid surface fitted to the gravimetric geoid h gravimetric-geometric geoid model of an area or a region. The detailed procedures which consist of selection of suitable/evenly distributed points, DGPS and gravity observations of selec of gravimetric geoid heights of the points, fitting of geometric geoid surface to the computed gravimetric geoid heights and computation of accuracy of the geoid model are presented in se